Freight car underframe with hydraulic cushioning



June 1, 1965 ANGOLD 3,186,562

FREIGHT CAR UNDERFRAME WITH HYDRAULIC CUSHIONING Filed Aug. 11, 1958 7Sheets-Sheet 1 J. A. ANGOLD June 1, 1965 7 Sheets-Sheet 2 Filed Aug. 11,1958 3 H V NW M m W J 2;}: :5: J H U \m M 1 1w: 1 1: d M L; 2 W W W .fl

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June 1, 1965 J. A. ANGOLD 3,136,562

FREIGHT CAR UNDERFRAME WITH HYDRAULIC CUSHIONING Filed Aug. 11. 1958 7Sheets-Sheet v3 fizaenim J. A. ANGOLD 3,186,562

FREIGHT CAR UNDERFRAME WITH HYDRAULIC CUSHIONING June 1, 1965 7Sheets-Sheet 4 Filed Aug. 11. 1958 s June 1', 1965 J. A. ANGOLD3,186,562

FREIGHT CAR UNDERFRAIE WITH HYDRAULIC CUSHIONING Filed Aug. 11. 1958 7Sheetfiheet 5 I 'l J I June 1,19 5 7 J. A. ANG OLD- 3,186,562

FREIGHT CAR UNDERFRAME WITH HYDRAULIC CUSHIONING I h I: Q va; Bay .4

- g I 'jnz/emfar' 5 .w v u 1 0? 0252503625.

United States Patent 3,186,562 FREEGHT CAR UNDERFRAME WITH HYDRAULIC(IUSHIQNING John A. Angold, Topeka, Kane, assignor to Keystone Thisinvention relates to a railway car underframe construction wherein ahydraulic cushioning device is disposed to act between a floating silland the fixed underframe for supplementing the cushioning action of theusual draft gears, which in this instance are disposed in the floatingsill. More particularly, the invention is concerned with providingbetter protection to car lading, with particular emphasis being placedon the elimination of impact damage at the higher coupling speeds, whichat the present time can sometimes result in serious damage to the caritself. Normal handling procedures prescribed by the A.A.R. define fourmph. as the accepted coupling speed, but, on occasion, the actualcoupling speed not infrequently may run as high as twelve to fifteenm.p.h., andsuch speeds have resulted in excessive lading damage.

While protection to lading is paramount, such protection must beachieved without imposing excessive strains on the car underfrarneconstruction. This problem of providing an economical car underframeconstruct-ion capable of properly cushioning high-speed coupling impactsfor insuring safe handling of lading is a major one in modern railroadtechnology, and certainly one of the most expensive.

It will be appreciated that, while the car-coupling speeds during yardclassification operations are of greatest significance, high impactloads are also applied to cars during normal train operation due toslack run in and slack run out, such as results when a long train movesinto a steep-sided valley or over the hump of a hill.

Accordingly, the principal object of this invention is to reduce theimpact shocks imparted to a freight car and the lading therein duringclassification and train operations. Briefly, this is accomplished witha cushioned underframe construction that includes a floating center sillhaving the usual draft gear devices at its opposite ends and connectedto the fixed underfra-me structure through a hydraulic cushioning unitthat is arranged in line within the floating sill to provide a longtravel, energy absorption stroke for dissipating the high energy impactloads with a minimum of reaction to the car structure. The hydrauliccushioning unit is a double-acting device selectively reacting inopposite directions between the floating center sill and the fixedunderframe structure.

Other objects and advantages will become apparent during thecourse ofthe following description.

In the accompanying drawings forming a part of this specification, andin which like numerals areemployed to designate like parts throughoutthe same:

FIG. 1 is a fragmentary perspective view of a car under-frameconstruction in accordance with this inven tion, with parts thereofbroken away for clarity of illustration;

FIG. 2 is a detailed sectional view illustrating the construction andarrangement at one of the bolsters of the underframe, and is taken onthe line 2-2 of FIG. 1; FIG. 3 is a detailed sectional view illustratingthe construction and arrangement at a typical cross bearer of theunderframe, and is taken along the line 33 of greases Patented June 1,1965 FIG. 6 is a semi-diagrammatic elevational view through thecushioning unit, with parts thereof being shown in exploded relation,with the upper half of the figure being in section and the lower halfbeing in elevation;

FIG. 7 is an elevational view through the assembled parts at one end ofthe hydraulic unit, with the upper half being shown in section; and

FIGS. 8A to 8B are graphs of the results of various performancecharacteristics of a car equipped with a cushioned underframe inaccordance with this invention.

Referring now to the drawings and particularly to FIGS. 14 thereof, thecar frame comprises a main underframe structure 26 providing a centralguideway 21 extending lengthwise therethrough and a rigid, elongatedcolumn 22 disposed in the guideway and supported from the underfrarnestructure for lengthwise sliding movement through the guideway. Thisslidable column 22 is hereinafter termed a floating sill, and, as isapparent from FIGS. 2 and 3, it has conventional double Z bars providingcontinuous top and side walls, and it is open along its bottom side toreceive and house the various cushioning instrumentalities andcooperating stop abutments that are provided in accordance with thepresent invention.

In the illustrated form of this invention, these instrumentalitiesconsist of a double-ended hydraulic cushioning unit 24 fixed to theopposed side walls of the floating sill centrally therealong, pistonstop assemblies 25 fixed to the main underframe structure at positionsadjacent opposite ends of the hydraulic cushioning unit 24, returnspring assemblies 26 disposed in the floating sill at positionsoutwardly of the outer ends of the piston stop assemblies 25, andreacting between the floating sill and the main underframe structure torestore the floating sill, and hence the hydraulic unit, to theirneutral centered position lengthwise in the main frame, and draft gearmechanisms 27 positioned in conventional draft pockets 23 provided inthe floating sill and operatively connected with the usual yoke 2? andcoupler 30. For convenience in illustration, one end portion of the mainframe, including its associated return spring assembly 26 and draft gearmechanism 27, has been omitted; but it will be understood that both endsof the car frame are of identical construction.

, The general operation of this equipment will be apparent. Thehydraulic unit 24 is a double-ended device and acts both in butt and indraft to cushion and absorb impact energy applied through the coupler 3dat either end of the car. Forces applied through the coupler aretransmitted to the floating sill through the draft gear mechanism 27,and then are transmitted from the floating sill to the main framethrough the fluid system of the hydraulic cushioning unit 24, with boththe draft 'gear mechanism and the hydraulic cushioning unit initiallyacting simultaneously in cushioning and absorbing the energy of theseforces. Closure travel of the draft gear mechanism is substantiallycompleted well before that of the hydraulic unit, and the hydraulic unitabsorbs the major share of the energy while maintaining reaction forcesto the car frame at an acceptable level. This is accomplished by virtueof the long travel stroke (ten inches), which is permitted in thehydraulic unit as compared with the three or four inch maximum travel ofthe draft gear mechanism. The novel construction of the hydraulic unitfor absorbing a maximum of energy under impact loading is describedhereinafter.

The main underframe structure comprises lengthwise extending side sills31; a pair of back-to-back, laterally spaced, lengthwise extending,channel-shaped Center sill members 32 that border and define theguideway 21; end sills 33; cross-bearer and crosstie members designated34- and 35, respectively, connecting the side sills 31 to the centersill members 32; and bolster members 36.

The bolster framing details are shown in FIG. 2, which illustrates themanner in which the bolster members 36 mate flush with the edges of thechannels 32 with a top tie plate 37 interconnecting the top sides of thebolster members and with a dished bolster center plate 38 havingupwardly inclined lateral extensions 38E partially underlying andinterconnecting the bottom sides of the bolster members. with lateralextending, depending ribs 38R (see FIG. 4) to strengthen theconstruction.

The framing details of the cross-bearers adjacent the hydraulic unit 24are shown in FIG. 3, which illustratesthe manner in which thecross-bearer members 34 mate flush with the lateral edges of thechannels 32, with a tie plate 4% being bridged across the floating silland interconnect,-,

The bolster center plate is preferably, provided ing the top sides ofthe cross-bearer members, and with I pending reinforcement ribs 41R tostrengthen the construction.

It will be apparent, th erefore, that the guideway 21gis bounded bycontinuous walls at its lateral extremities and by a number oflongitudinally spaced tie members at its upper and lower sides. Thevarious tie members sup-' The bottom porting and connecting the channels32 of the main underframe for supporting the floating sill within theguideway are apparent in FIG. 4, and include the bolstercenter plate 38,the bottom plates diet the cross-bearers and cross" ties which supportthe piston stop assemblies 25, and numerous additional bottom tiemembers as indicated at 42.

The floating sill 22 is also provided with a number of bottom tiemembers, some of which. (as shown at 44) are disposed beneath and serveas carriers for the hydraulic unit; some of which (as shown at 45) aredisposed beneath the piston stop assemblies and the remaining ones (as.shown at 46) are spaced along and give added rigidity to the floatingsill. Ateach end of the floating sill, solid stops are provided in theform of bottom tie plates 47 arranged on opposite ends of the bolstercenter plate 38 and spaced therefrom for abutment with the bolstercenter plate in positively limiting travel of p the heating sill. In thepreferred arrangement of this disclosure, these stops plates 47 arearranged to accommodate ten inches of travel.

The hydraulic unit 24 and the return spring assemblies stops for each ofthese assemblies, with the stops being a unique mounting relationshipvand mode of operation which facilitates its use in conjunction with afloating center sill structure and results in achieving a' significantelimination of lading damage at the higher coupling speeds; for example,12 mph. T he hydraulic mechanism is arranged symmetrically withinthefloating sill and functions therein as a double-ended in-line unitthat supplies a maximum cushioning effect While requiring a minimum ofmounting space. ts mounting location :within the floating sillsimplifiesthe underframe structure. The inline action of the deviceminimizes the'establishment of damaging stresses, both in the underframeand in the floating sill, and is believed to contribute importantly inachieving the desired uniform response, of the hydraulic unit undershock loads. The hydraulic unit has the addi- I cushioning stroke, andthis is done by'providing a hydraulic fluid friction systemthat'develops, a progressively increasing resistance ,to flow formaintaining the required pressures in the hydraulic system, even thoughthe speed of closure progressively decreases throughout the length ofthestroke; i V I As a further feature, the hydraulic unit is free ofdamaging recoil, with the return spring assembly 26 being depended uponfor restoring thefloating sill and the hydraulic mechanism itself to itssymmetrically neutral position centrally in the car. In this connection,the hydraulicmechanism develops a desirably low resistance during therestoring stroke.

The details of construction of the hydraulic mechanism are best shown inFIGS. 5 and 6. The mechanism includes the hollow, generally squareshaped-outer casing 59 which, in addition 'to forming a convenientstructure for attachment to the floating sill and for thereceptionarranged within the hollow floating sill and accommodating in-linemounting of the return spring assemblies, and particularly of thehydraulic unit;

7 Since the hydraulic unit is double acting, it has its outercasing-like main body 50 anchoredto the side walls 228 ing, bridge-liketie structure '52 that carries a separate face plate fixed at itsinnerend for abuting engagement with the ad acent piston rod. The tiestructure has a generally channel-shaped, cross-sectional configuration,and is anchored fast to the bottom plates 41 of adjacent cross-bearerand crosstie' members.

Each return spring assembly 26. comprises a pair of vertically spaced,horizontally extending coil springs 64 reacting between a stop platestructure" 65 suitably fixed to the floating sill and a spring stopassembly 66 anchored to the bolster center plate 38. The spring stopassembly I 66 carries an abutment plate structure 668 providing seatingengagement for the outer ends of the coil springs;

In the preferred form of the invention, as illustrated I herein forpurposes of disclosure, the hydraulieunit 24 has and securement of theparts of the hydraulic mechanism, also provides a lubricant reservoirand recirculation chamber forlthe hydraulic fluid. The hollowhousing'provides a generally square mounting chamberdl having an overalllength of about 34 and a height and width of 11%,

with thechamber opening through circular-holes 52 at its opposite ends,these holesbeing bounded by corner flanges SilF provided on the housingfor anchoring reservoir end castings 53 that cooperate witha doubleacting piston 54, an open ended cylinder 55, and cylinder head castings56.

The various partsot' the hydraulic unit are best shown in FIG. 6,which-illustrates one end of the unit in exploded, aligned relation. Itwill'be understood that the unit is preferably.symmetrical, and thatboth ends are of identical construction. For convenience, the variousparts of the unit are described individually, and thereafter their orderofassembly and mode of interaction are described. i

The end casting 53 has a generally square, cross-sectional shape toprovide mating corner portions that are provided with countersunk holesSST-l ter attachment bolts 503 that are engaged in the-corner flanges,50F of the housing. Each" end casting is formed Withan axial pistonrodpassage753P having a diameter slightly greater than that ofrthe pistonrod,.with a snitablebearing sleeve 57 provided therein adjacentto the"usual piston rod sealing facilities, which may includeV-shaped sealingelements 59V compacted betweena packing gland'plate59 and'a pressureringofl under a pre-determinedaxial loadplate .59 carries awiplerfr'inging established: by coil springs'tiLejThepacking gland centric with thepistonfrod, V r 1 I a The end casting has an inwardly projectingfrusto-con 59R that is maintained conisease cial shape, as indicated at58, to provide a structural backing of desired length and strength forthe bearing sleeve 5'7. Finally, the end casting is provided with adrilled bore 5313 for supplying hydraulic fluid to the system after theparts are assembled, with the bore opening through an otherwisecontinuous, annular locating shoulder 538 provided about the outermargin of an annular, intermediate face 53F provided on each end of thecasting. The outside diameter of the shoulder 538 is approximately 11%.In addition, a groove 53G extends peripherally through the generallysquare shaped, inwardly directed face of the casting and receives asuitable gasket ring for sealing cooperation with the adjacent end ofthe reservoir housing St).

Each end casting cooperates with an adjacent cylinder head casting 56having the general form of a circular ring to provide a central passagefor the piston rod, and including an integral, outwardly projectingmarginal annular wall 56W that terminates in end face 56F arranged forabutting engagement with the intermediate end face 53F of the adjacentend casting. This integral annular wall forms a central pocket 56F,which receives the tap ering, inner end portion 58 of the end castingwith a suitable clearance being provided for a required hydraulic fluidreturn circuit, as will be described. A part of this circuit is providedby radially extending holes 56H that are drilled through the integralannular wall at spaced points about the periphery thereof to place thepocket in communication with the reservoir chamber.

The cylinder head is provided with a series of axial passages 56A inannular arrangement through its transverse faces, with these passagesbeing blocked by a check valve mechanism 62 during the cushioningmovement of the piston, and being exposed by release of the check valvemechanism during the return movement of the piston. The check valvemechanism comprises a sealing ring 62R resiliently pressed against theinner face of the cylinder head by a plurality of bolt and springassemblies 62A, which normally maintain the sealing ring in maskingsealing relationship across the inner ends of the passages, and whichaccommodate axial displacement of the sealing ring from the cylinderhead to admit hydraulic fluid to the cylinder during the return stroke.Finally, the cylinder head has an annular recess 56R about the outermargin of the outer face formed by the annular wall 56W, with thisrecess being complemental to and receiving the locating shoulder 538 ofthe end casting to fixthese parts in aligned engagement.

The outside diameter of the cylinder head is approxirnately il /s"inches, and it therefore fits loosely within the reservoir chamber.Engagement of the shoulder 533 in the recess 56R centers the cylinderhead with respect t? tlle end casting, and hence with respect to thereservoir 1 se The hydraulic cylinder 55 has an overall length of 26%",and is centered lengthwise within the reservoir housing 50, so that ateach end the cylinder is set back from the end of the housing asufficient distance to accommodate the cylinder heads and part of theend castings within the housing. The cylinder has an outer diameter of11 /3", and, when positioned in engagement with the cylinder heads, ismaintained centered within the reservoir chamber to provide a minimumclearance between the walls of the reservoir housing and the cylinder onthe order of A5. To provide this centered engagement, the inner face ofeach cylinder head is formed with a marginal recess for receiving theadjacent end face 55F of the cylinder. It will be apparent, however,that the square shape of the housing leaves appreciable clearances atthe corner regions of the reservoir chamber to provide this chamber withthe desired fluid capacity. Maintaining The cylinder receives thesymmetrical, double-ended piston and rod structure 5 preferably havingthe piston rods 54R formed integrally therewith and projecting coaxiallyfrom the opposite end faces of the double-ended piston 54F. It will benoted that this symmetrically arranged, double-ended piston structuremaintains constant volume relationships within the hydraulic unit, sinceas the piston is displaced in one direction from'its centered neutralposition the volume of the piston rod that is displaced at one end ofthe cylinder is exactly compensated by the other piston rod.

The hydraulic unit is preferably assembled on end. One reservoir endcasting 53 is supported with its central passage overlying an open pit.A cylinder head casting is placed on the end casting in pre-determinedaligned relationship, with these castings having mating dowel pinopenings facilitating this alignment.

It will be apparent from a consideration of FIG. 7 that the two castingsare brought together so that the annular shoulder 538 seats within theannular recess 56R of the head casting, with the flat, annular, opposingend faces 53F and 55F in abutting engagement. The reservoir housing isthen applied over the assembled castings and supported with its end faceresting on the gasket ring. The cylinder and piston may then be applied,it being noted that the end of the cylinder is received in the annularlocating recess provided on the inner face of the cylinder head castingto maintain the cylinder in a centered, properly spaced position withinthe reservoir chamber of the housing. Finally, the other cylinder headand reservoir end are applied, and the bolts 50B are engaged between thereservoir housing and reservoir ends. When finally assembled, thecylinder is under axial compression by virtue of direct metal-to-metalcontact between the ends of the cylinder and the cylinder heads, andbetween the cylinder heads and the reservoir end castings. Theclearances are selected so that the gasket ring is under a predeterminedcompression between the ends of the housing and the reservoir endcastings, but these parts are not in direct metal-to-metal contact.

After assembly of the parts is completed and with the unit in ahorizontal position, as indicated in FIGS. 6 and 7, hydraulic fluid isintroduced through the passage 53B in the end castings, and it flowsaround the cylinder head and the cylinder to the reservoir chamber, andalso flows through a radial passage 56K in the cylinder head to the headcasting pocket 56F to ultimately fill the cylinder itself. The reservoiris filled to the level L (see FiG. 7) to proyide suflicient air spacefor expansion of the hydraulic fluid. The mechanism is then insertedupwardly into the floating sill and secured therein, with the tie plates44 being removable for accommodating insertion and removal of thehydraulic unit.

As mentioned previously, when the hydraulic mechanism is in place withinthe floating sill its functions in conjunction with the draft gearmechanisms in cushioning impact loads applied through the couplers; and,being double acting, it responds both in buff and in draft in handlingloads applied from either end of the car. In the hydraulic mechanism,the impact loads applied from the floating sill to the reservoir housingact to displace the housing from its centered, neutral positionlengthwise of the under frame, while the piston rods 54R abut againstthe piston stop assemblies and maintain the piston stationary withrespect to the underframe.

As will be apparent, the cylinder heads and reservoir ends move as aunit with the housing, and the relative movement of these parts withrespect to the piston is cushioned, while the energy of impact isdissipated by hydraulic fluid friction developed under the influence ofhydraulic fluid pressures that are established and maintained in thecylinder. In accordance with the invention, these pressures aremaintained at a high and generally uniform level throughoutthe'cushioning stroke.v This is best done by arranging thefriction-producing fluid passages so that their effective areaprogressively decreases throughout the I passage area is constantthroughout the length of the stroke. A piston operating in a straightbore with a PI'EGB-C termined constant peripheral clearance is typical.

The preferred fluid passage arrangement may be'cmbodied in a number ofways; for example, the cylinder through which the piston moves may bemade slightly larger than the piston to provide flow passages in theform of peripheral clearances; In this case, the bore of the cylindervis tapered from a maximum at the center to a minimum at each end.Alternatively, the cylinder may have a straight bore of uniform,circular cross-section with the flow passages being formed by providinggrooves" lengthwise in the cylinder walls, with the size of the groovesbeing a maximum adjacent the center of the cylinder, and a minimum atthe opposite ends. In the preferred construction disclosed herein forpurposes of illustration, the cylinder 55 has a'straight bore ofuniform, circular cross-section cooperating with a piston having itscylindrical sealing wall formed with a pair of axially spaced grooves54G to receive a pair of piston ringsin continuous sealing engagementwith the cylinder wall. In this disclosure, the cylinder wall isprovided with an arrangement of axially spaced orifice. openings 55-0(see FIGS. and 6). communicating between the reservoir chamber and thecylinder. These orifice openings are preferably located to feed directlyinto the corner regions of the reservoir chamber, and this minimizesfluid frictional resistance in'the return circuitthat is established forthe hydraulic fluid during the operating stroke 'of the unit. Thisreturn circ'uit is completed through a set of enlarged holes 55Hprovided approximately centrally along the length of the cylinder atspaced points about the periphery thereof.- These enlarged holes'aremasked by the piston when it is in its centered, neutral position, andare progressively ex-.

be' cor-related with: the return spring assemblies to provide for arapid andcasyreturn of the piston.

The performance characteristics of a cushioned underframe, in accordancewith this invention, are illustrated in the graphs of FIGS. 8A to 8B.Reference should I first be had, however, to the curve ofpFlG. 8D, the

' that were niadeover a, range of impact speeds.

tests, a moving car Was coupled with a capacity-loaded ordinate of whichindicates the effective orifice area at car standing at rest and backedup byisix empty cars which had their air'brakes set. Only the moving carhad the cushioned underframe of this invention. actual tests, thecushioned underframe was provided with arubber draft gear, while theadjacent endfof the standing car was provided with'a friction draftgear, and these, two draft 7 gear mechanisms functioned with thehydraulic mechanism in cushioning and dissipating the energy of impact.

Under these conditions, therefore, the curve of FIG.

' 8A illustrates that-the travel or displacement of the posed as thepiston is displacedtoward one end of the a a cylinder.

It will be immediately apparent that, as the piston is moved toward theend of the cylinder and fluid isfor'ced from the cylinder chamber andthrough the orifice openings, the pressure within the cylinder isdependent'upon the. size of these orifices and upon the speed of travelof the vpistonerelative to the cylinder., The piston speed reaches amaximum shortly after impact, and is there after reduced as the pistonis brought to rest, preferably immediately before the positivestops canengage. While the piston speed decreases, fluid pressures are maintainedgenerally uniform by arranging the'orifices to provide a correspondinglydecreasing effective orifice area. It will be apparent that, as'thepiston is displaced toward the end of the cylinder, it progressivelymasks and bypasses more 'duced, and this arrangement avoids adangerousstress-- 'ing of the housing 50. I a

When the impact loading is removed, the returnspring assemblies 26 reactbetween the main frame and the floating sill-to restorethe parts totheir centered neutral 7 position; and, 'as the piston'returnsthrough-the cylinder,

hydraulic, fluid flows principally through the enlarged holes 551-1,through the reservoir chamber, and then.

through the' radial holes 56H in the cylinder. head to force open thecheck valve ring 62R and refill the previously evacuated chamber. Itwill be apparent that this piston from its centered neutral position isapproximately 9 /2" at a 12 mph. 'coupling' speed, and is reduced only.to about 6 for al mph. coupling speed; It is significant that, evenat'speedsof 12 mph, the 10" allowable :t'ravelis not fully used up.While solid stops come into play'after 10 of travel, it isimportant'that this be avoided wherever possible in order to eliminateundesirable shocks that may damage not'only the lading but theunderframe structure itself.

It is also interesting that for the lowerspeeds the hydraulic mechanismdevelops a relatively long cushioning stroke, and this,'of course,permits it to handle im pacts at these speedsquite effectively.

The curve of FIG. 8B is believed to be sel -explanatory in that it showsthe approximateacceleration or deceleration which the carundergoes forthe range of coupling speeds. Similarly, curve 8C is self-explanatory,and it illustrates the coupling force developed at various impactspeeds; This is the force that is applied throughthe coupler andtransmitted through the floating sill and the hydraulic mechanism to thepiston stop, assembly,

. which then distributes it to the underframe. Even for amplifier thatfeeds into a recording oscillograph. It 7 should be understoodrthatthere .is no output from the accelerometer immediately prior to impact.or when the parts are finally brought to a rest condition; The velocitycurve rises rathersharplyat impact, and then drops off: to extend belowthebase'line until the rest condition is attained. Considering" thatthefhorizontal base line defines a constant rate of change ofvelocityfrom impact speed to the rest condition, theisvelocity :curve of FIG.SEindicates that. the acceleration or deceleration is' somewhat greaterthan average during the .fluid circuit provides a low-resistant fiowpathydepende ing on the adjustment of the check valve; and this may.

initial closure,-and. it is thereafter. somewhat lesser than average, v4 Y i I Thus, .it may be 'seen'thattheobjects of this inven- 'tion havebeenaccomplished in that the ,hydraulic mechanism, when embodied morefloating sill of acushioned undcrframe, rnarkedlyreducescoupling forcesapplied to the car, and hen'ce better protects the .lading;

f The in-line'lmounting of the hydraulic ni cchanism In the simplifiesthe fabrication of the underframe structure and facilitates assembly ofthe unit within the underframe while also minimizing dangerous stressconditions in the underframe, and particularly in the floating sill.Important advantages also exist from the standpoint of maintenance,particularly in connection with the provision of the reservoir, whichtests indicate has never been subjected to a pressure greater than 70pounds per square inch. Similarly, the pressures at the piston rodsealing arrangement are held within this range, and this greatlyminimizes maintenance problems.

It should be understood that the description of the preferred form ofthe invention is for the purpose of complying with Section 112, Title35, of the US. Code, and that the claims should be construed as broadlyas the prior art will permit.

I claim:

1. In combination, an underframe structure having a guideway extendinglengthwise therethrough, a channel shaped unitary floating sillstructure in the guideway to project from opposite ends thereof andslidably supported from the underfrarne structure, a hydrauliccushioning unit disposed in the floating sill structure and including adouble-ended hydraulic cylinder lengthwise in the guideway and fixed tothe floating sill structure and a double-ended piston and piston rodassembly slidable lengthwise in the cylinder to develop hydraulic fluidpressure therein, with the piston rods projecting from opposite ends ofthe cylinder to abut with cooperating stops fixed to the underfrarnestructure and projecting within the floating sill structure adjacentopposite ends of the assembly, said unit having means providing ahydraulic fluid flow path between opposite ends of the cylinder fordeveloping fluid frictional resistance to relative lengthwise movementbetween the cylinder and the assembly so that the unit resists relativelengthwise movement between the structures by developing hydraulic fluidfriction under hydraulic pressure, and a separate return spring assemblydisposed within the floating sill structure in lengthwise outwardlyspaced relation from each end of the hydraulic cushioning unit and eachincluding resilient lengthwise extending spring means reacting betweenan inner stop abutment fixed to the floating sill structure in alignmentwith the hydraulic unit and an outer stop abutment fixed to a bolstercenter plate of the underframe structure and projecting upwardly intothe floating sill structure and aligned with the hydraulic unit.

2. In combination, an underframe structure having a guideway extendinglengthwise therethrough, a channel shaped unitary floating sillstructure in the guideway to project beyond opposite ends thereof andslidably supported from the underframe structure, a hydraulic cushioningunit disposed in the floating sill structure and ineluding adouble-ended hydraulic cylinder lengthwise in the guideway and fixed tothe floating sill structure and a double-ended piston and piston rodassembly slidable lengthwise in the cylinder to develop hydraulic fluidpressure therein, with the piston rods projecting from opposite ends ofthe cylinder to abut with cooperating stops fixed to the underframestructure and projecting within the floating sill structure adjacentopposite ends of the assembly, said unit having means providing ahydraulic fluid flow path between opposite ends of the cylinder fordeveloping fluid frictional resistance to relative lengthwise movementbetween the cylinder and the assembly so that the unit resists relativelengthwise movement between the structures by developing hydraulic fluidfriction under,

unit and being aligned horizontally for positive engagement.

3. The arrangement of claim 2, wherein a bolster center plate of theunderframe structure functions as one of said stops.

4. In combination, an underframe tructure comprising opposedhorizontally extending channel members defining a lengthwise extendingguideway that is open at the bottom, side sills extending parallel toand flanking the channel members, end sills connecting the ends of theside sills and channel members, and a plurality of cross-bearer andcrosstie members connecting the side sills to the channel members atspaced points therealong, a channel shaped unitary floating sillstructure disposed lengthwise in the guideway, with the underframestructure including bottom tie members bridging the guideway andslidably supporting the floating sill structure therein, piston stopassemblies disposed in alignment within the floating sill and spacedapart lengthwise on opposite sides of the transverse center line of theunderframe structure, said assemblies each comprising a bridging memberextending lengthwise between and fixed to bottom plates of adjacentcross-bearer and crosstie members to provide cooperating lengthwisespaced horizontally aligned stops, and a hydraulic cushioning unitdisposed in the floating sill structure and including a double-endedhydraulic cylinder lengthwise in the guideway and fixed to the floatingsill structure and a double-ended piston and piston rod assemblyslidable lengthwise in the cylinder to develop hydraulic fluid pressuretherein, with the piston rods projecting from opposite ends of thecylinder to abut with the piston stop assemblies, said unit having meansproviding a hydraulic fluid flow path between opposite ends of thecylinder for developing fluid frictional resistance to relativelengthwise movement between the cylinder and the piston assembly so thatthe unit resists relative lengthwise movement between the structures bydevelop ing hydraulic fluid friction under hydraulic pressure.

5. In combination, an underframe structure having a guideway extendinglengthwise therethrough, a channel shaped floating sill structure in thegui eway and slidably supported from the underframe structure, and ahydraulic cushioning unit disposed in the floating sill structure andcomprising a double-ended hydraulic cylinder lengthwise of the guideway,an outer casing housing the cylinder and forming a reservoir chambertherearound for hydraulic fluid, a double-ended piston and piston rodassembly extending lengthwise through the cylinder with the piston rodsthereof projecting from opposite ends of the cylinder to abut withcooperating stops fixed to the underfrarne structure and projectingwithin -the floating sill structure adjacent opposite ends of theassembly, and cylinder heads Within the casing in telescoping relationover the piston rods and sealing with the cylinder at opposite endsthereof, said unit providing a hydraulic fluid flow path for developingfluid frictional resistance to relative lengthwise movement between thecylinder and the assembly such that the unit resists relative lengthwisemovement between the structures, each head having fluid flow passagemeans extending therethrough to connect between the cylinder andreservoir chamber and said cylinder having fluid return holes centrallytherealong opening into the reservoir chamber to compl-etea hydraulicfluid return circuit, with the fluid return holes being masked by thepiston when the piston is in a neutral centered position within thecylinder, with each head having check valve means normally blocking flowoutwardly through the head as thepiston is moved toward such head,thereby developing hydraulic fluid pressure Within the cylinder, saidcheck valve means being yieldable to accommodate flow inwardly throughthe head.

6. The arrangement of claim 5, wherein the hydraulic fluid flow path fordeveloping fluid frictional resistance to relative lengthwise movementbetween the cylinder and the assembly is provided in-the form of holesopening through the periphery of the cylinder, said holes beingdistributed along the length of the cylinder such that the eflectiveorifice area thereof progressively decreases during the cushioningstroke of the hydraulic unit.'

7. The arrangement of claim 5, wherein the hydraulic unit includesseparate reservoir end castings in telescoping relation over the pistonrods and in direct abutment with the adjacent cylinder head, and meansfor securing the, end castings to the casing with the endcastings-holding the cylinder heads in compression against the cylinder,with each end casting having peripheral sealing means in sealingengagement with the adjacent end of the casing,

and with each end casting being formed with a plugged filling borecommunicating with the reservoir chamber and with the outer end of theadjacent cylinder head.

8. In combination, anunderframe structure comprising opposedhorizontally extending channel members defining a lengthwise extendingguideway that is open at the bottom, side sills extending parallel toand'flanking the channel members, end sills connecting the ends of theside sills and channel members, and a plurality of crossbearer andcrosstie members connecting the side sills to the channel members atspaced points therealonga channel shaped floating sill structuredisposed in the guideway, with the underframe structure including bottomtie members bridging the guideway and slidably supporting the floatingsill structure therein, piston stop assemblies disposed within thefloating sill and spaced apart length- 'WlSE/ on opposite sides of thecenter line of the underframe structure, said assemblies each comprisingabridging member extending lengthwise-between and fixed to bottom platesof adjacent cross-bearer and crosstie members to provide cooperatinglengthwise spaced horizontally aligned stops, and a hydraulic cushioningunit disposed 'in, the floating sill structure and comprising adoubleended hydraulic cylinder lenghwise of the guideway, an.

outer casing housing the cylinder and'forming areservoir chambertherearound for hydraulic fluid, a double-ended piston and piston rodassembly ext-ending lengthwise through the cylinder with the piston rodsthereof projecting from opposite ends of the cylinder to abut with thepiston stop assemblies, and cylinder heads within the casing intelescoping relation over the piston rods and sealing with the cylinderat opposite ends thereof, said unit providing a hydraulic fluid flowpath for developing fluid frictional resistance to relative lengthwisemoveended hydraulic cylinder lengthwiseof the guideway, an

outer casing housing the cylinder and forming a reservoir chambertherearound for hydraulic fluid, a double-ended piston and piston rodassembly extending lengthwise through the cylinder with the piston rodsthereof projecting from opposite ends of the cylinder to abut with thepiston stop assemblies, and cylinder heads within the casing intelescoping relation over the piston rods and sealing with the cylinderat opposite ends thereof, said unit providing a hydraulic fluid flowpath for'developing fluid frictional resistance to relative lengthwisemovement between the cylinder and the assembly such that the unitresists relative lengthwise movement between the structures, each headhaving fluid flow passage means extending therethrough to connectbetween the cylinder and reservoir chamber and said cylinder havingfluid return 7 holes centrally therealong opening into the reservoirchamber to complete a hydraulic fluid return circuit, With the fluidreturn holes being masked by the piston when the piston 'is in 'aneutral centered position within the cylinder,-with each headhavingcheck valve means normally blocking flow outwardly through the head asthe ment between the cylinder and the assembly such that i the unitresists'relative lengthwise movement between the structures, each headhaving fluid flow passage means" extending therethrough to connectbetween the cylinder and reservoir chamber and said cylinder havingfluid re-' turn holes centrally. therealong opening into the reservoirchamber to complete a hydraulic fluid return circuit, with the fluidreturn holes beingmasked by the piston when the piston is in a neutralcentered position within the cylinder, with each head having check valvemeans normally blocking flow outwardly through the head as the piston ismoved toward such head, thereby developing hydraulic fluid pressurewithin the cylinder, said check valve means being yieldable toaccommodate flow in-t wardly through the head. 7 i

9. In combination, an underframe structure comprising opposedhorizontally extending channel members dew fining a lengthwise extendinguideway that is open at the bottom, side sills extendingparallelto andflanking the channel members, end sillsconnecting the ends of the sidesills andchannel members, and a plurality of cross bearer and crosstiemembers connecting the side sills to the channel members at spacedpontstherealong, a channel shaped floating sill structure disposed in theguideway,

with the underframe structure including bottom tie mem- 'bers bridgingthe guideway and slidably supporting the floating sill structuretherein, said floating sill structure piston is moved-toward such head,thereby'developing hydraulic fluid pressure within the cylinder, said'check valvemeans being'yieldable to accommodate flow in-' wardlythrough-the head. i

1%. In combination, an underframe structure having a guideway open, atthe bottomaand extending lengthwise through the underframe structure, achannel-shaped floating sill structure having anro'pen bottomandlsupported from the underframe structure for lengthwise slidingmovementin the guideway, said floating sill structure extending thelength of said guideway and having aligned draft pockets adjacentopposite ends thereof, adratt gear mechanismoperatively mounted in eachpocket, coupling mechanism to each draft gear mechanism fortransmitt-ing butt and draft impact forces therethrough to thefloatingsill structure, and a double-acting hydraulic cushioning unittdisposedin the floating sill structure intermediately betweenand aligned withthe draft pockets and including a double-ended hydraulic cylinderlengthwise of the guideway and fixed'to the floating sillstructure andadoubleended piston and 'pistonrod assembly slidable in the cylinder todevelop hydraulic fluid pressuretherein, with t the piston 'rods'projecting from opposite ends of the cylinder to abut with cooperatingstopsflxed tothe underframe structure and projecting 'withinfthe'floating sill structure adjacent opposite ends'of the assembly, saidhydraulic unit includingan outer casing housing the cylinder and forminga reservoir chamber therearound for hydraulic fluid, and cylinder headswithin the casing in having aligned draft pockets adjacent opposite endsthere of, a draft gear mechanism ioper'atively mounted in each positionwithin thecylinder;

telescoping relation over the piston rods to seal'the cylinder atopposite ends: thereof, each head having fluid flow passage-meansextending therethrOughtoconnect between the cylinder and "reservoirchamber, with each head having check valve means normally blocking flowoutwardly through the headand yieldable to accommodate flowinwardlylthrough the head; and said cylinder having fluid-return holescentrallytherealong'opening 7 into the reservoir chamber to complete ahydraulic fluid return 'circ'uitpwith the -'fluid-ret,urn, holes beingmasked, neutral centered by the pistonwhenthe piston is in a- 11 Thearrangement of claim 1d wherein the hydraulic unit includes separatereservoir end castings in sealing, telescoping relation over the pistonrods and in direct, sealing abutment with the ends of the casing andmeans for securing the end castings to the casing with the end castingsholding the cylinder heads against the cylinder to provide alow-pressure space between each end casting and the cylinder headadjacent thereto, each said space serving as a fluid flow passagebetween the cylinder and the reservoir chamber.

12. In combination, an underframe structure having a guideway extendinglengthwise therethrough, a channelshaped floating sill structure in the.guideway and slidably supported from the underfrarne structure, and ahydraulic cushioning unit disposed in the floating sill structure andcomprising a double-ended hydraulic cylinder lengthwise of the guideway,an outer casing housing the cylinder and forming a reservoir chambertherearound for hydraulic fluid, a double-ended piston and piston rodassembly extending lengthwise through the cylinder with the piston rodsthereof projecting from opposite ends of the cylinder to abut withcooperating stops fixed to the underframe structure and projectingwithin the floating sill structure adjacent opposite ends of theassembly, and cylinder heads within the casing in telescoping relationover the piston rods and sealing with the cylinder at opposite endsthereof, said unit providing a hydraulic fluid flow path for developingfluid frictional resistance to relative lengthwise movement between thecylinder and the assembly such that the unit resists relative lengthwisemovement between the structures, each head having fluid flow passagemeans extending therethrough to connect between the cylinder andreservoir chamber, with each head having check valve means normallyblocking the flow outwardly through the head as the piston is movedtoward such head, thereby developing hydraulic fluid pressure within thecylinder, said check valve means being yieldable to accommodate flowinwardly through the head.

13. In combination, an underframe structure comprising opposedhorizontally extending channel members defining a lengthwise extendingguideway that is open at the bottom, side sills extending paralleltoandflanking the channel members, end sills connecting the ends of theside sills and channel members, and a plurality of crossbearer andcrosstie members connecting the side sills to the channel members atspaced points therealong, a channel-shaped floating sill structuredisposed in the guideway, with the underframe structure including bottomtie members bridging the guideway and slidably supporting the floatingsill structure therein, piston stop assembliesidisposed within thefloating sill and spaced apart lengthwise on opposite sides of thecenter line of the underframe structure, said assemblies each comprisinga bridging member extending lengthwise between and fixed to bottomplates of adjacent cross-bearer and crosstie members to providecooperating lengthwise spaced horizontally aligned stops, and ahydraulic cushioning unit disposed in the floating sill structure andcomprising a double-ended hydraulic cylinder lengthwise of the guideway,an outer casing housing the cylinder and forming a reservoir chambertherearound for hydraulic fluid, a double-ended piston and piston rodassembly extending lengthwise through the cylinder with the piston rodsthereof projecting from opposite ends of the cylinder to abut with thepiston stop assemblies, and cylinder heads within the casing intelescoping relation over the piston rods and sealing with the cylinderat opposite ends thereof, said unit providing a hydraulic fluid flowpath for developing fluid frictional resistance to relative lengthwisemovement between the cylinder and the assembly such that the unitresists relative lengthwise movement between the structures, each headhaving fluid flow passage means'extending" therethrough to connectbetween the cylinder and reservoir chamber, with each head having checkvalve means normally blocking flow'outwardly through the head as thepiston is moved toward such head, thereby developing 1d hydraulic fluidpressure within the cylinder, said check valve means being yieldable toaccommodate flow inwardly through the head.

14. A hydraulic cushioning unit comprising a doubleended hydrauliccylinder, an outer casing housing the cylinder and forming a reservoirchamber therearound for hydraulic fluid, a double-ended piston andpiston rod assembly extending lengthwise through the cylinder with thepiston rods thereof projecting from opposite ends of the cylinder, andcylinder heads within the casing in telescoping relation over the pistonrods and sealing with the cylinder at opposite ends thereof, said unitproviding a hydraulic fluid flow path for developing fluid frictionalresistance to relative lengthwise movement between the cylinder and theassembly, each head having fluid flow passage means extendingtherethrough to connect between the cylinder and reservoir chamber, witheach head having check valve means normally blocking flow outwardlytherethrough as the piston is moved toward such head, thereby developinghydraulic fluid'pressure within the cylinder, said check valve meansbeing yieldable to accommodate flow from the reservoir chamber inwardlythrough the head. I

15. In combination, an underframe structure having a guideway extendinglengthwise therethrough, a channelshaped floating sill structure in theguideway and slidably supported from the underframe structure, and ahydraulic cushioning unit disposed in the floating sill structure andcomprising a double-ended hydraulic cylinder lengthwise of the guideway,an outer casing housing the cylinder and forming a reservoir chambertherearound for hydraulic fluid, a double-ended piston and piston rodassembly extending lengthwise through the cylinder with the piston rodsthereof projecting from opposite ends of the cylinder to abut withcooperating stops fixed to the underframe structure and projectingwithin the floating sill structure adjacent opposite ends of theassembly, and cylinder heads within the casing in telescoping relationover the piston rods and sealing with the cylinder at opposite endsthereof, said cylinder having holes spaced along the length thereofforming a reversible hydraulic fluid flow path between opposite ends ofthe cylinder, said flow path including the reservoir chamber.

16. In combination, an underframe structure having a guideway extendinglengthwise therethrough, a channelshaped floating sill structure in theguideway and slidably supported from the underframe structure, and ahydraulic cushioning unit disposed in the floating sill structure andcomprising a double-ended hydraulic cylinder lengthwise of the guideway,an outer casing housing the cylinder and forming a reservoir chambertherearound for hydraulic fluid, a double-ended piston and piston rodassembly extending lengthwise through the cylinder with the piston rodsthereof projecting from opposite ends of the cylinder to abut withcooperating stops fixed to the underframe structure and projectingwithin the floating sill structure adjacent opposite ends of theassembly, and cylinder heads within the casing in telescoping relationover the piston rods and sealing with the cylinder at opposite endsthereof, said unit having means providing a reversible hydraulic fluidflow path between opposite ends of the cylinder for developing uniformfluid frictional resistance characteristics to relative lengthwisemovement in either direction between the cylinder and the pistonassembly.

17, In combination, an underframe tructure having a guideway extendinglengthwise therethrough, a channelshaped floating sill structure in theguideway and slidably supported from the underframe structure, and ahydraulic cushioning unit disposed in the. floating sill structure andcomprising a double ended hydraulic cylinder lengthwise of the guideway,an outer casing housing the cylinder and forming a reservoir chambertherearound for hydraulic fluid, a double-ended piston and piston rodassembly extending lengthwise through the cylinder with the piston rodsthereof projecting from opposite ends of the cylinder V to abut withcooperating stops fixed to the underframe structure and projectingwithinthe floating sill structure adjacent opposite ends of the assembly, andcylinder heads within the casing in-telescoping relation over the pistonrods and sealing with the cylinder at opposite ends thereof, 1

separate reservoir end castings in telescoping relation over the pistonrods andin direct abutment with the adjacent cylinder head, means forsecuring the end castings to the casing; with the end castings holdingthe cylinder heads in compression against the cylinder, with each endcasting having peripheral sealing engagementwith the adjacent end of thecasing, and means providing a reversible hydraulic fluid-flow pathbetween oppositerends of the cylinder for developing uniform fluidfrictional resistance characteristics to relative lengthwise movement ineither; direction between the cylinder and the piston,

assembly.

18. In combination, an underfname structure having a guideway extendinglengthwise therethrough, a rigid elongated unitary column structure inthe guideway to ported from said underframe structure, a hydrauliccushioning mechanism disposed within said guideway intermediatelytherealong and including a hydraulic cylinder lengthwise in the guidewayand a piston and piston rod assembly slidable in the cylinder to develophydraulic fluid pressure therein, said mechanism having flow restrictingmeans providing a hydraulic fluid flow path between oppositesides of thepiston for developing fiuid'frictional resistance to relative lengthwisemovement between the cylinder and the assembly, and abutment means onone of said structures engaging said cylinder at 1 one end of saidmechanism and abutment means on the other of said structures engagingsaid assembly at the opposite end of said mechanism so that themechanism resists relative lengthwise-movement in either direction 7between the structures by developing hydraulic fluid friction underhydraulic pressure.

'19. The combination of claim 18 further characterized by the provisionof spring means for returning said cushioning mechanism'to its initialposition following an 20 project beyond opposite endsgthereof andslidably, sup-' in, V structure to the vehicle body, an auxiliary sillextending longitudinally within said center sill structure and adaptedto movevlongitudinally with respect thereto and having a neutralposition,;a coupler and 1a draft' rigging arranged within said'auxiliary' sill structure adjacent said first end of said body, acoupler and a draft rigging arranged within said auxiliary sillstructure adjacent said second end of said body, means connecting each,driaft rigging to said auxiliary sill structure whereby it is movedrelative to said center sill structureupon application of an impact toeither coupler, a cylinder mounted Withinsaid auxiliary sill structure,means, securingithe cylin der to the center sill structure, a pistonmovable within said cylinder and arranged in a central position thereininrthe neutral posia railway vehicle body, a center sill structureextending longitudinally of said bodyand secured thereto, an auxiliarysill structure extending longitudinally withinjsaid center sillstructure and arranged'for lengthwise movements with'respect to thecenter s'ill structure, resilient means maintaining said auxiliary sillstructure in a new tral position with respect to the center sillstructure, a coupler and a draft riggingiarranged within the auxiliarystructure, means connecting said draft rigging to said auxiliary-sillstructure, a cylinder mounted within said sill structures, meansincluding transversely spaced block impact force against either end ofsaid column structure. 1

26'. In a railway car: a longitudinally extending hollow center'sillfixed to the car; asliding center, sill member longitudinally slidablymounted in said fixed center sill; cooperating stop means carried bysaid fixed center si l and said sliding member limiting longitudinalmovement of said member; resilient means biasing said member to aneutral position; a double-acting, hydraulic, piston-and cylinder buffermechanism having a first external coupling element connected to thepiston and a second external elements secured to said. centersillstructure engaging the respective ends of the cylinder. maintaining itin a fixed position withrespectto the center: sill structure, a pistonmounted for movement within'ithe cylinder, a rod carried 'by said pistonextending towards the coupler through the associated end of the cylindenliquid within said cylinder,

' an abutment member carried by the: auxiliary sill structure spacedfrom one end of the cylinder in the neutral position of the auxiliarysill structure, means carried by said abutment member engaging saidpiston: rod in the neutral position of the'auxiliary sill structure, andsaid cylinder having a metering opening throughwhich said liquid isforced by movement of the piston.

coupling element connected to the cylinder; means connecting one of saidcoupling elements to said slidingmember;.and means connecting the otherof said coupling elements to said car.-

21. In a railway car: a longitudinally extending hollow center-sillfixed to the car; a sliding center sill mounted longitudinallyslidablymounted in said fixed center sill and extending substantially theentirelength of saidfixed center sill;'cooperating stop means carried bysaid fixed center sill and said sliding member limiting longitudinalmovement of said member;resilient meansbiasing said member to a neutralposition midway between. the limits ofmovement of said member; adou'bleracting, hydraulic,

piston-and-cylinder buffer mechanism having a first ex ternal couplingelement connected to the piston and a second external coupling elementconnected to the cylin. der; means connecting one of said couplingelements to said sliding member; andrmeans connecting the other of saidcoupling elements to said fixed center sill.

22. A cushion mechanism for a railway vehicle fQr ab fsorbing theenergyof an impact applied to, a coupler thereof comprising, a railway vehiclebody, a center sill structure; extending longitudinally of said bodyfrom a first end to a second end, means fixing the center sill 24.A'mechanism for absorbing the energy of an impact appliedto a coupler ofarrailway vehicle comprising, a railway vehicle body, a center'sillstructure extending longitudinally of said body andisecured thereto, an

auxiliary sill vstructure extending longitudinally within' saidcentersill' structure and arranged for lengthwise movements with respect tothecenter sill structure, resilient means maintaining saidauxiliary-sillstructure in a neutral position with respect to the"center sillistructure, a coupler and a draft rigging arranged withineach end of; the auxiliary sill structure, means connecting each draftrigging to said auxiliary sill structure, a cylinder,

mounted within the mid-portion of said centersill' structure,transversely'spaced block elements secured a; said center ,sillstructure engaging the respective ends of the cylinder maintaining it ina-fixed position with respect to the center sill structure, a pistonmountedfor movements withinthe cylinder and having a rmidposition-thereinin the neutral position ofthe auxiliarysill'structure,-fa piston rod carried ,by'the'piston extending-fromeachend ofthe cylinder, liquid substantially filling, said cylinder,abutment-members 'carr'iedi by :the auxiliary sill structure spaced fromthe associated block elements in the neutral position of the auxiliary'sill structure, a prOjectionczirried 'l)y:each abutment member engagingan end of said piston rod, and said cylinder "having a plurality ofmetering grooves in the wall thereof through which said liquid is forcedupon relative movements of the piston with respect to the cylinder.

25. A cushion mechanism for a railway vehicle for absorbing the energyof an impact applied to a coupler thereof comprising, a vehicle body, acenter sill structure extending longitudinally of said body and securedthereto, an auxiliary sill structure extending lengthwise within saidcenter sill structure arranged for movements longitudinally relative tosaid center sill structure, a coupler and a draft rigging carried by anend portion of said auxiliary sill structure, means coupling said draftrigging to said auxiliary sill structure for moving the auxiliary sillstructure relative to said center sill structure upon application of animpact to said coupler, a cylinder mounted within said auxiliary sillstructure, a piston within said cylinder, a piston rod extending throughopposite ends of said cylinder, liquid within said cylinder, meanscarried by the auxiliary sill structure in abutting relationship withone end of said piston rod, means carried by the auxiliary sillstructure in abutting relationship with the other end of said pistonrod, members carried by the center sill structure engaging opposite endsof said cylinder preventing longitudinal movements of the cylinderrelative to the center sill structure, and means for controlling theflow of liquid from one side of said piston to the other side thereof tocushion movements of the auxiliary sill structure relative to the centersill structure.

26. A cushion mechanism for a railway vehicle for absorbing the energyof an impact applied to a coupler thereof comprising, a vehicle body, acenter sill structure extending longitudinally of said body and securedthereto, an auxiliary sill structure extending lengthwise within saidcenter sill structure arranged for movements longitudinally relative tosaid center sill structure, a coupler and a draft rigging carried by anend portion of said auxiliary sill structure, means coupling said draftrigging to said auxiliary sill structure for moving the auxiliary sillstructure relative to said center sill structure upon application of animpact to said coupler, a cylinder mounted within said auxiliary sillstructure, a piston within said cylinder, a piston rod extending throughopposite ends of said cylinder, liquid within said cylinder, memberscarried by one of said sill structures in abutting relationship with theopposite ends of said cylinder, members carried by the other of saidsill structures in abutting relationship with opposite ends of saidpiston rod to produce relative movement between the piston and thecylinder during relative movement of the auxiliary sill structure andthe center sill structure, and means metering movement of said liquidduring relative movement of the piston and the cylinder.

27. A cushion mechanism for a railway vehicle for absorbing the energyof an impact applied to a coupler thereof comprising, a vehicle body, acenter sill structure extending longitudinally of said body and securedthereto, an auxiliary sill structure extending lengthwise within saidcenter sill structure arranged for movements longi- 18 tudinallyrelative to said center sill structure, a coupler and a draft riggingcarried by an end portion of said auxiliary sill structure, meanscoupling said draft rigging to said auxilary sill structure for movingthe auxiliary sill structure relative to said center sill structure uponapplication of an impact to said coupler, a cylinder mounted within saidauxiliary sill structure, a piston within said cylinder, a piston rodextending through opposite ends of said cylinder, liquid within saidcylinder, means securing said cylinder against axial movements withrespect to said center sill structure, members carried by the auxiliarysill structure in abutting relationship with opposite ends of saidpiston rod to produce relative movement between the piston and thecylinder during relative movement of the auxiliary sill structure andthe center sill structure, and means metering movement of said liquidduring relative movement of the piston and the cylinder.

28. A cushion mechanism for a railway vehicle for absorbing the energyof an impact applied to a coupler thereof comprising, a vehicle body, acenter sill structure extending longitudinally of said body and securedthereto, an auxiliary sill structure extending lengthwise within saidcenter sill structure arranged for movements longitudinally relative tosaid center sill structure, a coupler and a draft rigging carried byeach end portion of said auxiliary sill structure, means coupling saiddraft riggings to said auxiliary sill structure for moving the auxiliarysill structure relative to said center sill structure upon applicationof an impact to either coupler, a cylinder mounted within said auxiliarysill structure, a piston within said cylinder, a piston rod extendingthrough opposite ends of said cylinder, liquid within said cylinder, acenter post structure secured to said center sill structure in abuttingrelationship with one end of said piston rod, stop means carried by thecenter sill structure in abutting relationship with the other end ofsaid piston rod, lugs carried by the auxiliary sill structure engagingopposite ends of said cylinder preventing longitudinal movements of thecylinder relative to the auxiliary sill structure, and said cylinderhaving grooves therein controlling the velocity of flow of the liquidfrom one side of the piston to the other to cushion movements of theauxiliary sill structure relative to the center sill structure.

References Cited by the Examiner UNITED STATES PATENTS Meyer et a1.21343 LEO QUACKENBUSH, Primary Examiner. JAMES S. SHANK, Examiner.

Disclaimer 3,186,562.J0lm A. Angold, Topeka, Kans. FREIGHT CAR UN DER-FRAME 'WITH HYDRAULIC CUSHIONING. Patent dated June, 1, 1965. Disclaimerfiled N 0v. 26, 1965, by the assignee, Keystone Railway EquipmentCompany. Hereby enters this disclaimer to claims 18, 19, 22, 23, 24, 25,2'6', 27 and 28 of said patent.

[Ofiicz'al Gazette May 10, 1966.]

